While it's still controversial, medical marijuana is edging toward normality. Forty states (and the District of Columbia) now have some form of law on the books that allow the drug to be used for a variety of ailments, and sales are soaring— reaching $5.4 billion in 2015.

That doesn't mean it's widely available in all of those states, of course. Some, like Alabama and South Carolina, have extremely strict circumstances under which cannabidiol products can be prescribed, and still forbid the production and distribution of the drug. And even in states where it's easier to come by, there are differences in how it's handled.

California — The first state to legalize medical cannabis, California is a leader in the industry. In 2015, it passed a bill that will create a centrally regulated dispensary system. ASA says the state is "the best place in the country for patients to receive legal protections and gain the most timely access" to the drug, but it falls a bit short on implementing employment, housing and child custody protections for patients. Rating: B+

Colorado — In this state, medical and recreational marijuana are legal. Access to the drug is plentiful, and patients are offered discount medicine in case of financial hardship. And there are few zoning regulations in the state, meaning a dispensary is generally not hard to find. ASA, however, notes there is a lack of civil protection for users. It also dings the state for passing off product safety requirements to the cities and counties, rather than overseeing them on a statewide level. Rating: B

Hawaii — The ASA likes the Aloha State's dispensary legislation, but notes there are no recall protocols in place for the product, and no independent testing lab requirements. Also hurting the state's score: lengthy delays for patients to get the ID cards required to fill a prescription. However, the state got very high marks for protecting patient rights. Rating: B

Illinois — Illinois is credited "with adopting some of the best product safety regulations in the country." The regulations allow state officials to test for harmful pesticides, microbes, solvents and poisons from fungus. About the only quibbles the group had with the state were its mandatory fingerprint background checks for new patients and the inability of patients to grow their own plants. Rating: B+

Maryland — While Maryland is given credit for its approach to product safety, the ASA says access to medical marijuana falls short of other states, in part because of likely delays in licensing dispensaries and in part due to high patient demand. The state waited 2½ years before it began issuing business licenses to dispensaries and cultivation centers and has struggled to process nearly 900 applications. The state also scores low on civil protections for users who are concerned about their child custody rights and their status on organ transplant lists. Rating: B

Massachusetts — The Bay State is one of just three that gives physicians the leeway to recommend medical marijuana to any patient, presuming the benefits outweigh the risks. (Washington and Hawaii are the others.) That alone, says the ASA, gives it the potential to have "one of the nation's premier medical cannabis programs." The group, says it would like to see patient rights beefed up, though, and a faster turnaround for dispensary licensing. Rating: B

Nevada — Patients are easily able to obtain medical marijuana, and product safety is ranked highly in this state. The ASA's chief complaint is Nevada's low possession limits of 2.5 ounces (— lowest smng the marijuana states — which could prevent some patients from having an uninterrupted supply. Rating: B+

New Mexico — New Mexico has made some big strides since the ASA's last state rankings, nearly doubling the number of dispensaries to 17. That helped it earn a higher rating this year. Its biggest hole was patient protection in areas like child custody, housing and employment. Rating: B+

Oregon — The state has "one of the strongest medical cannabis programs for patients in the nation," according to the ASA. Access to medicine is widespread, and the laws are patient-friendly and offer explicit privacy protections. The ASA is urging Oregon officials not to merge the medical program with the one that will oversee the casual-use program. Rating: B

Washington — Washington has scaled back its medical marijuana program, recently shutting down dozens of dispensaries in Tacoma and Seattle after legislative changes. But it still earns top marks for patient rights and product safety. How it might rank next year is nebulous, though, since collective gardening rights — where up to 10 patients can band together to grow their own plants — are due to expire in July. This could result in some supply constraints. Rating: B